Episode descriptions for the penultimate episodes of The Flash and ArrowThe CW has released the episode descriptions for the penultimate episodes of both The Flash and Arrow, setting the stage for their season finales at the end of May.The Flash episode 2.22 is titled “Invincible” and is officially described as follows:“After Zoom (guest star Teddy Sears) unleashes an army of Earth-2 meta-humans on Central City, Barry is shaken when he sees their leader is the Black Canary’s Earth-2 doppelganger, the Black Siren (guest star Katie Cassidy).